The present invention relates generally to ambulatory orthopedic restraining devices such as casts, braces and the like. More particularly, the present invention relates to communication of orthopedic parameters from the restraining devices to a central monitoring station.
It is known that both muscles and bones should be exercised to maintain strength. It is also known that healing fractures, exposed to permissible weight bearing stress, often heal more predictably and more rapidly than fractures which are not stressed at all. This is probably also true for connective tissues, such as ligaments and articular cartilage.
When an individual sustains a physical injury which involves damage to bones, muscle tissue, connective tissue or the like, the physician treating the individual will make a determination as to whether exercise will be allowed The physician will allow exercise if the physician can obtain assurances that the exercise will be performed in a controlled manner within specific parameters wherein the injured bone and/or tissue will remain stable. Unfortunately, however, the physician is generally unable to obtain adequate information or assurances about the manner in which a particular patient will conduct prescribed exercise. Furthermore, because the physician is also unable to obtain adequate feedback after the patient performs any specific prescribed exercise, the physician generally does not feel he or she has sufficient access to information about the exercise to permit or recommend anything but the most basic exercise. Without some way to obtain information about exercise events, the physician cannot maintain sufficient control of the exercise. The physician does not know how much stress the patient can or will exert voluntarily, and does not know how well the patient will adhere to a schedule of repetitive exercise events.
Since the physician is not able to obtain adequate feedback regarding the patient""s exercise, the most prudent course of action for the physician is to limit the amount of exercise which the patient is allowed to perform by immobilizing the portions of the body proximate the injury. This is often accomplished by using a cast which is the simplest and crudest method of protecting an injury. The cast allows virtually no movement at all and is widely used to insure against reinjuries. Unfortunately, this method of protecting the injury often does not provide adequate means for exercising the body portions proximate the injury. For instance, a cast is often not strong enough, without additional reinforcement, to permit isometric exercising. Furthermore, casts are not equipped to provide feedback to the physician or the patient with respect to any exercising.
Accordingly, a need exists for a personal orthopedic restraining device which will permit and encourage a range of exercise during rehabilitation and provide sufficient feedback to the prescribing physician to allow the physician to evaluate the patient""s progress in regard to the exercise the physician has prescribed. A need also exists for a personal retraining device which is equipped to give the patient immediate feedback respecting exercise events. Although it has been known that exercise is helpful in rehabilitating patients and others having orthopedic disabilities, inadequacies, or the like, adequate devices for methods of retraining respective body parts and monitoring the exercise thereof have not been provided which adequately address this problem. This monitoring can be enhanced by utilizing a central monitoring station which receives orthopedic parameters through a communication system.
Communication systems take many forms. In general, the purpose of a communication system is to transmit information-bearing signals from a source, located at one point, to a user destination, located at another point some distance away. A communication system generally consists of three basic components: transmitter, channel, and receiver. The transmitter has the function of processing the message signal into a form suitable for transmission over the channel. This processing of the message signal is referred to as modulation. The function of the channel is to provide a physical connection between the transmitter output and the receiver input. The function of the receiver is to process the received signal so as to produce an estimate of the original message signal. This processing of the received signal is referred to as demodulation.
One type of communication system is a spread-spectrum system. In a spread-spectrum system, a modulation technique is utilized in which a transmitted signal is spread over a wide frequency band within the communication channel. The frequency band is much wider than the minimum bandwidth required to transmit the information being sent. A voice signal, for example, can be sent with amplitude modulation (AM) in a bandwidth only twice that of the information itself. Other forms of modulation, such as low deviation frequency modulation (FM) or single sideband AM, also permit information to be transmitted in a bandwidth comparable to the bandwidth of the information itself. However, in a spread-spectrum system, the modulation of a signal to be transmitted often includes taking a baseband signal (e.g., a voice or data channel) with a bandwidth of only a few kilohertz, and distributing the signal to be transmitted over a frequency band that may be many megahertz wide. This is accomplished by modulating the signal to be transmitted with the information to be sent and with a wideband encoding signal.
Three general types of spread-spectrum communication techniques exist, including direct sequence modulation, frequency and/or time hopping modulation, and chirp modulation. In direct sequence modulation, a carrier signal is modulated by a digital code sequence whose bit rate is much higher than the information signal bandwidth.
Information (i.e., the message signal consisting of voice and/or data) can be embedded in the direct sequence spread-spectrum signal by several methods. One method is to add the information to the spreading code before it is used for spreading modulation. It will be noted that the information being sent must be in a digital form prior to adding it to the spreading code, because the combination of the spreading code and the information typically a binary code involves modulo-2 addition. Alternatively, the information or message signal may be used to modulate a carrier before spreading it.
These direct sequence spread-spectrum communication systems can readily be designed as multiple access communication systems. For example, a spread-spectrum system may be designed as a direct sequence code division multiple access (DS-CDMA) system. In a DS-CDMA system, communication between two communication units is accomplished by spreading each transmitted signal over the frequency band of the communication channel with a unique user spreading code. As a result, transmitted signals are in the same frequency band of the communication channel and are separated only by unique user spreading codes. These unique user spreading codes preferably are orthogonal to one another such that the cross-correlation between the spreading codes is low (i.e., approximately zero).
Particular transmitted signals can be retrieved from the communication channel by despreading a signal representative of the sum of signals in the communication channel with a user spreading code related to the particular transmitted signal which is to be retrieved from the communication channel. Further, when the user spreading codes are orthogonal to one another, the received signal can be correlated with a particular user spreading code such that only the desired user signal related to the particular spreading code is enhanced while the other signals for all of the other users are de-emphasized.
It will be appreciated by those skilled in the art that several different spreading codes exist which can be used to separate data signals from one another in a DS-CDMA communication system. These spreading codes include but are not limited to pseudonoise (PN) codes and Walsh codes. A Walsh code corresponds to a single row or column of the Hadamard matrix.
Further it will be appreciated by those skilled in the art that spreading codes can be used to channel code data signals. The data signals are channel coded to improve performance of the communication system by enabling transmitted signals to better withstand the effects of various channel impairments, such as noise, fading, and jamming. Typically, channel coding reduces the probability of bit error, and/or reduces the required signal to noise ratio (usually expressed as bit energy per noise density (i.e., Eb/N0) which is defined as the ratio of energy per information-bit to noise-spectral density), to recover the signal at the cost of expending more bandwidth than would otherwise be necessary to transmit the data signal. For example, Walsh codes: can be used to channel code a data signal prior to modulation of the data signal for subsequent transmission. Similarly PN spreading codes can be used to channel code a data signal.
It will be appreciated by those skilled in the art that the use of these spread-spectrum signals in a communication system is highly desirable, because under current federal communications commission (FCC) rules no license is required to operate such devices if particular frequencies are used.
The present invention provides a solution to these and other problems, and offers other advantages over the prior art.
The present invention provides a communication system for an instrumented orthopedic restraining device (e.g., a brace). This communication system transfers therapeutic information (e.g., an orthopedic parameters signal) between a patient wearing a brace and a doctor or technician who is monitoring the healing progress of the patient from a remote location.
In accordance with a first aspect of the invention, a communication unit is provided. The communication unit includes a data input which receives an orthopedic parameters signal representative of a sensed stress in a personal orthopedic restraining device. The sensed stress preferably is a value representative of a total torque output by the individual over a period of time as measured by the personal orthopedic restraining device. The restraining device is designed to restrain movement of a first flexibly connected body portion relative to a second flexibly connected body portion of an individual who is wearing the restraining device. An encoder is operatively coupled to the data input to protect the received orthopedic parameters signal from potential transmission errors by encoding the received orthopedic parameters signal. A modulator is operatively coupled to the encoder to prepare the encoded orthopedic parameters signal for subsequent transmission by modulating the encoded orthopedic parameters signal. Finally, a transmitter is operatively coupled to the modulator to transmit the modulated orthopedic parameters signal over a communication channel such that movement of flexibly connected body portions can be monitored by a central site monitoring station.
The data input preferably includes a mechanism (e.g., buttons, a keypad, touch screen, or the like) for incorporating messages obtained from the individual into the orthopedic parameters signal for transmission to the central site monitoring station. In addition, the orthopedic parameters signal preferably further includes a patient identifier which can be used to identify a particular set of data from a patient at the central station from among several other sets of data pertaining to other patients.
It will be appreciated by those skilled in the art that several encoding techniques exist including interleaving, block coding, convolutional coding, and cyclical redundant coding. In addition, several forms of modulation exist. The encoded orthopedic parameters signal can be modulated according to a communication access type selected from the group consisting of: frequency division multiple access, time division multiple access, and code division multiple access. Also, the communication channel may be one of several types of channels including: an electronic data bus, radio communication link, wireline, optical fiber link, and/or satellite link. The type of communication channel can also be described with reference to a particular channel known in the art. Some of the possible currently existing channels that may be used include a serial port wireline, a parallel port wireline, a public switched telephone network (PSTN), a private data network, a radio data network, a paging channel, a short message service channel, a personal communications service channel, a trunked radio channel, a cellular radio channel, and/or a satellite link.
The communication unit also includes a detachable connection mechanism for selectively connecting the communication unit to the personal orthopedic restraining device. This will allow the patient to attach the communication unit only when needed as well as provide for easy replacement of the communication unit should it need repair or maintenance. The communication unit also has a power supply (e.g., a rechargeable battery) which is detachably connected to the personal orthopedic restraining device and the communication unit. The power supply preferably is shaped and arranged for optimal positioning on the individual which will be wearing the personal orthopedic restraining device and the communication unit.
In some instances, it may be necessary for the individual wearing the restraining device to get a message from the central station or for the communication unit/restraining device to receive instructions from the central station. Therefore, the communication unit is also configured with a receiver for receiving a communication from the central site monitoring station over the communication channel. The central site monitoring station communication may take many forms including: a message to the individual wearing the personal orthopedic restraining device and the communication unit, a programming instruction for the personal orthopedic restraining device, a request for an orthopedic parameter signal from the personal orthopedic restraining device, a request to resend a portion of an orthopedic parameter signal previously sent by the personal orthopedic restraining device, and/or confirmation that a previous orthopedic parameter signal was received. As a result of some of these communications, the communication unit may need to provide the central site monitoring station communication to the personal orthopedic restraining device and has a data output provided for such purposes.
In accordance with a second aspect of the invention, a central site monitoring station communication unit is provided. The central site monitoring station communication unit includes a receiver for receiving a modulated orthopedic parameters signal from a personal orthopedic restraining device worn by an individual. The modulated orthopedic parameters signal is representative of a sensed stress in the restraining device. A demodulator is operatively coupled to the receiver to demodulate the received modulated orthopedic parameters signal. A detector is operatively coupled to the demodulator to detect an orthopedic parameters signal from demodulated orthopedic parameters signal. Also, data output is operatively coupled to the detector to provide the detected orthopedic parameters signal to an external device such that subsequent processing of the orthopedic parameters signal can be performed.
As previously noted with respect to the communication unit attached to the restraining device, the central site monitoring station communication unit preferably is adapted for use with a variety of different types of communication channels and different modulation schemes. Also, the detector preferably includes a mechanism for detecting transmission errors in the demodulated orthopedic parameters signal. In addition to detecting the errors, the detector preferably includes a mechanism for correcting some types of transmission errors in the demodulated orthopedic parameters signal based on a maximum likelihood sequence estimation algorithm.
The central site monitoring station communication unit also includes a transmitter for transmitting a communication from the central site monitoring station over the communication channel to the personal orthopedic restraining device. This communication, as previously noted, can have several different contents, including: a message to the individual wearing the personal orthopedic restraining device and the communication unit, a programming instruction for the personal orthopedic restraining device, a request for an orthopedic parameter signal from the personal orthopedic restraining device, a request to resend a portion of an orthopedic parameter signal previously sent by the personal orthopedic restraining device, and/or confirmation that a previous orthopedic parameter signal was received.
It may be desirable for subsequent processing to be done to communications received from the personal orthopedic restraining device and as such an external device can be coupled to the central site monitoring station communication unit. The external device preferably processes the orthopedic parameters signal. This orthopedic parameters signal is a sensed stress value representative of a total torque output by the individual over a period of time as measured by the personal orthopedic restraining device. Some of the types of subsequent processing that the external device may perform include: comparing the sensed stress value to an expected value to confirm that the individual""s responses are within norms, comparing the sensed stress value to previously received values associated with a patient identifier for the individual to judge the individual""s response to treatment, storing the sensed stress value along with previously received values associated with a patient identifier for the individual to create a clinical record, monitoring a prescribed exercise regimen of the individual based on the sensed stress value to monitor compliance with the prescribed exercise regimen, performing statistical analysis of the sensed stress value in conjunction with other values received at the central site monitoring station, providing a message obtained from the individual wearing the personal orthopedic device to another individual at the central site monitoring station, and/or determining a programming instruction to be sent to the personal orthopedic restraining device.
These first and second aspects of the invention also can be implemented in device-implemented methods to communicate an orthopedic parameters signal between a remote communication unit and a central site monitoring station. This communication method includes receiving the orthopedic parameters signal at the remote communication unit from a personal orthopedic restraining device. Subsequently, the received orthopedic parameters signal are protected from potential transmission errors by encoding the received orthopedic parameters signal. The encoded orthopedic parameters signal is prepared for subsequent transmission by modulating the encoded orthopedic parameters signal. Then, the modulated orthopedic parameters signal is transmitted over a communication channel from the remote communication unit and to the central site monitoring station such that movement of flexibly connected body portions can be monitored by the central site monitoring station.
The device-implemented method also preferably includes storing two or more different orthopedic parameters signals before transmitting any signals such that modulated versions of the stored two or more orthopedic parameters signals are transmitted in a single transmission burst over the communication channel. This storing technique can be used to reduce the overall power consumption of a communication unit by reducing the average number of transmissions that a communication unit performs in a given time period.
The device-implemented method may consist of only a one-way communication scheme in which case several provisions about the operation of the communication unit must be made. For example, the receiving component in the communication unit may be limited to only activate after a particular action has occurred. These actions may be a prescribed exercise regimen having been completed, a periodic reporting time having occurred, at least two different orthopedic parameters signals having been generated by the personal orthopedic device, and/or a message having been obtained from the individual for incorporation into the orthopedic parameters signal for transmission to the central site monitoring station.
Alternatively, the device-implemented method may include receiving a communication from the central site monitoring station over the communication channel such that a two-way communication scheme is performed. Once again, the receiving component in the communication unit may be limited to only activate after a particular action has occurred. These actions may include: a prescribed exercise regimen having been completed, a periodic reporting time having occurred, at least two different orthopedic parameters signals having been generated by the personal orthopedic device, a message having been obtained from the individual for incorporation into the orthopedic parameters signal for transmission to the central site monitoring station, and/or a communication having been received from the central site monitoring station which requests an orthopedic parameter signal from the personal orthopedic restraining device. If a communication is received from the central site monitoring station, then the communication preferably is provided to the personal orthopedic restraining device.
In the two-way communication scheme a limited-short or a full-long communication may be received from the central site monitoring station. The two types of communications may be distinguished by the amount of information contained in the message. Several communication channels currently have or are planning to have provisions for providing limited-short messages which are less expensive and more available than channels capable of full-long messages. Either type of message can be sent on a variety of channels including: a radio data network, a paging channel, a short message service channel, a personal communications service channel, a trunked radio channel, a cellular radio channel, and/or a satellite link. The limited-short communication which has a small information content may include: a request for an orthopedic parameter signal from the personal orthopedic restraining device, a request to resend a portion of an orthopedic parameter signal previously sent by the personal orthopedic restraining device, and confirmation that a previous orthopedic parameter signal was received. In contrast, a full-long communication may be any of those mentioned for the limited-short communication as well as a message to the individual wearing the personal orthopedic restraining device and the communication unit and/or a programming instruction for the personal orthopedic restraining device.
These and various other features as well as advantages which characterize the present invention will be apparent upon reading of the following detailed description and review of the associated drawings.